1902.] on the Electronic Theory of Electricity. 169 



made us acquainted with matter in a finer state of subdivision. For 

 a long time a controversy was carried on, whether the radiation in a 

 high vacuum tube which proceeds from the kathode was a material 

 substance or a wave motion of some kind. But no fact yet found is 

 inconsistent with the notion which originated with Sir William 

 Crookes that the transfer which takes place is that of something 

 which has the inertia quality of matter, and his term " radiant matter " 

 is a peculiarly suitable phrase to describe the phenomena. The great 

 advance which has since been made, by Professor J. J. Thomson and 

 others, is that of measuring accurately the amount of bending which 

 a stream of this radiant matter experiences under a known magnetic 

 force, and from this deducing the ratio between the mass of the 

 radiant particle and the electric charge carried by it. This measure- 

 ment shows that if the radiant matter consists of corpuscles or 

 particles, each of them carries a charge of one electron, but has a 

 mass of about one-thousandth of a hydrogen atom. 



The evidence therefore exists that Crookes' " radiant matter " (also 

 called the " kathode rays ") and Thomson's " corpuscles," are one and 

 the same thing, and that these corpuscles may be described as frag- 

 ments broken off from chemical atoms and possessing only a small 

 fraction of their mass. These particles are shot off from the negative 

 terminal or kathode of the vacuum tube with a velocity which is 

 from one-fifth to one-third the velocity of light. 



Moreover, it has been shown that when the kathode rays pass 

 through a thin metal window in a vacuum tube and get into the space 

 outside, thus forming Lenard's rays, they are likewise only the same 

 or similar corpuscles in the space outside rather than inside the 

 vacuum tube. Finally it has been proved that these electrified 

 corpuscles are present as well in the mass of a gas through which 

 Rontgen rays have passed, also in the mysterious radiation called 

 Becquerel rays which proceeds from uranium and other radio-active 

 substances, also in all flames, near all very hot bodies and in the air 

 near certain metallic surfaces, on which ultra-violet light falls. In 

 every case the corpuscle is charged with an electron charge of 

 negative electricity. If a corpuscle originates as a fragment chipped 

 off from an electrically neutral atom and is negatively charged, it 

 follows that the remainder of the atom of matter is left positively 

 charged. 



The word " atom " therefore, as far as it signifies something which 

 cannot he cut, is becoming a misnomer as applied to the chemical unit 

 of matter, because this latter is capable of being divided into two 

 parts of very unequal size. First, a small part which is negatively 

 electrified and which is identically the same, no matter from what 

 chemical atom it originates, and secondly, a much larger mass which 

 is the remainder of the atom and is positively electrified, but which 

 has a different nature depending on the kind of chemical atom broken 

 up. The question has then begun to be debated whether we can 

 distinguish between the corpuscle and the electric charge it carries. 



